BACKGROUND/AIM Temozolomide (TMZ) induces prolonged arrest of human glioma cells in the G2/M phase and inhibition of the G2 checkpoint intensifies the effect of TMZ. These findings suggest that the G2 checkpoint is linked to DNA repair mechanisms. MATERIALS AND METHODS To clarify the mechanism of TMZ resistance, we established TMZ-resistant (TR) clones by serial treatment of U87MG cells with TMZ. We evaluated TMZ-induced cell cycle arrest and the effect of various G2 checkpoint inhibitors. RESULTS We observed that longer exposure (over 6 months) to TMZ enriched the proportion of TR clones that underwent only minimal G2 arrest following TMZ treatment compared to short exposure (4 months) to TMZ. Expression of MSH6 was reduced in these clones. None of the G2 checkpoint inhibitors could resensitize TR clones to TMZ. CONCLUSION Longer drug treatment may induce resistance of cells to DNA damaging agent(s) by means of mismatch repair modification. BACKGROUND/AIM Malignant pleural mesothelioma (MPM) is an intractable cancer, and causes of its malignant transformation are not well known. Adenosine deaminase acting on RNA (ADAR) is an RNA-editing enzyme that converts adenosine into inosine in double-stranded RNAs potentially involved in malignant development. MATERIALS AND METHODS To examine the role of ADAR1 and ADAR2 in MPM, small interfering RNAs (siRNAs) against ADAR1 or ADAR2 were used. RESULTS Transfection of siRNA against ADAR2 suppressed proliferation, motility, and invasiveness of MPM cells expressing both ADAR1 and ADAR2; however, siRNA against ADAR1 did not affect these cellular activities. Overexpression of ADAR2, that was incapable of binding to RNA, suppressed growth, motility, and invasion of MPM cells. However, overexpression of ADAR2 that had no enzyme activity did not alter the malignant properties of MPM cells. CONCLUSION Enhancement of the malignant characteristics of cultured MPM cells via ADAR2 was independent of RNA-editing activity. AIM To investigate the association between adiponectin (ADIPOQ) genotypes and colorectal cancer (CRC) risk among Taiwanese. MATERIALS AND METHODS Polymerase chain reaction-restriction fragment length polymorphism was adopted to identify ADIPOQ rs266729, rs2241766 and rs1501299 genotypes among 362 CRC patients and 362 healthy controls. RESULTS ADIPOQ rs266729 GG genotype (p=0.0075) and G allele (p=0.0061) are associated with a significantly increased CRC risk. There is no differential distribution of rs2241766 and rs1501299 genotypes. As for the gene-lifestyle interaction, there are obvious joint effects of rs266729 genotype on the CRC risk among non-smoker, non-alcohol drinker, while not on smoker or non-drinker subgroups. No significant correlation was observed between rs266729 genotypic distributions and age, gender, tumor size, location or metastasis status. Interestingly, a correlation of rs266729 genotype and larger BMI on CRC risk was found. CONCLUSION G allele at ADIPOQ rs266729 may serve as a determiner for CRC risk, especially for those with BMI ?24. BACKGROUND/AIM The role of androgen receptor (AR) in hepatocellular carcinoma (HCC) development is controversial. Therefore, the translational value of targeting AR in HCC is unknown. Sorafenib, a multiple kinase inhibitor, is the standard therapy for patients with unresectable HCC. This study investigated sorafenib effect on AR in experimental models of HCC. MATERIAL AND METHODS AR cDNA was introduced into HCC cells and in vitro cell growth and in vivo tumor growth were measured. Sphere cells, as well as epithelial cell adhesion molecule-positive (EpCAM+) and CD133+ cells were isolated from HCC cells with/without AR expression to observe in vitro/in vivo effects. Liver specific AR knockout in mouse models of spontaneous HCC (carcinogen-induced and hepatitis B virus-related HCC) was also implemented to examine gene expression. HCC cells/tumors were treated with sorafenib in order to determine effects on tumor growth and related gene expression. RESULT AR cDNA increased transactivation function, increased coloth HCC, suggesting suitability of a sorafenib regimen for such patients. CONCLUSION AR+/EpCAM+ may be a marker of responsiveness to sorafenib for patients with HCC. Prospective surveys associating AR/EpCAM expression with therapy outcomes are essential. BACKGROUND/AIM We evaluated the influence of smoking on head and neck squamous cell carcinomas (HNSCC), which are in their majority tobacco-driven. Tobacco smoke is expected to influence the expression of ABCG2-transporters involved in multidrug resistance. The aim of the study was to evaluate the effect of cigarette smoke condensate (CSC) on ABCG2 expression on HNSCC cells, to demonstrate the adverse effects of cigarette smoke during anticancer treatment in vitro and to assess the prevalence of ABCG2 expression in HNSCC. MATERIALS AND METHODS HNSCC cell lines were treated with CSC and basal and induced ABCG2 expression was examined. The impact of CSC on cellular viability/proliferation during cytotoxic drug treatment was also evaluated. ABCG2 expression levels in HNSCC were correlated with the smoking history of patients. RESULTS HNSCC cells showed low basal ABCG2 expression. CSC treatment resulted in a threefold increase in the expression of ABCG2 and in resistance to cisplatin. Tumor samples of never smokers showed significantly higher ABCG2 expression compared to ever smokers. ABCG2 expression correlated with pack years of cigarette consumption. CONCLUSION Tobacco consumption is linked to an inducible and increased ABCG2 protein expression and has an impact on drug resistance. https://www.selleckchem.com/products/alflutinib-ast2818-mesylate.html BACKGROUND/AIM Pancreatic ductal adenocarcinoma (PDAC) and extrahepatic cholangio-carcinoma (eCC) represent two cancer entities with devastating prognoses. Despite recent progress in research and treatment, therapy remains challenging. Cancer stem cells (CSCs) have been shown to play an important role in metastasis and chemoresistance. Therefore, CSCs may play a promising role as a potential therapeutic target. MATERIALS AND METHODS A total of 31 patients (23 PDAC, 8 eCC) were included in the study. CSCs were analyzed in a single-cell suspension of tumor samples via fluorescence-activated cell scanning (FACS) with a functional Hoechst 33342 staining as well as a cell surface marker staining of the CSC-panel (CD24, CD44 and EpCAM) and markers to identify fibroblasts, leukocytes and components of the notch signaling pathway. Furthermore, the potential presence of CSCs among primary cancer-associated fibroblasts (CAFs) was assessed using the same FACS-panel. RESULTS We showed that CSCs are present in patient-derived dissociated tumor tissue.